The Watts LF709-DOSY 4 is a 4" lead-free double check valve assembly, approved for low health hazard protection. It features a cast iron body. Rated to 175 psi. This model is certified lead-free for potable-water installations.
This 4 inch lead free double check valve backflow preventer assembly is designed to prevent the backflow of polluted water from entering into the potable water supply due to backsiphonage and or backpressure. Its compact modular design facilitates easy maintenance with a single access cover for in-line repairs. It is ideal for protection in continuous pressure piping applications and at cross-connections identified as non-health hazards. This assembly consists of an fused epoxy coated cast iron body, domestic outside stem and yoke resilient seated gate valves, top mounted test cocks, two in-line independent positive seating check modules, captured springs, and replaceable check discs and seats. The coating on this backflow assembly uses ArmorTek®, a patented 3-part advanced epoxy coating system designed to limit both microbial induced (MIC) and exposed metal substrate corrosion.
Features
- Utilizes advanced ArmorTek coating technology to resist corrosion of internals
- Cast iron body construction with patented 3-part advanced epoxy coating system designed to limit both microbial induced (MIC) and exposed metal substrate corrosion
- Domestic outside stem and yoke gate valves
- Maximum flow at low pressure drop
- No special tools required for servicing
- Includes: Test Cocks
Common Questions
- What hazard level is this Double Check approved for?
- It is rated for low health hazard (non-toxic, "pollutant") cross-connections only. Where the substance downstream could be a health hazard, codes require a reduced pressure zone (RPZ) assembly instead. The assembly is listed to ASSE 1015.
- Is this model legal for potable water?
- Yes. It is certified lead-free to NSF/ANSI 372, which is what state plumbing codes require for any device in a drinking-water line.
- Does this assembly have to be tested every year?
- Yes. This is a field-testable assembly with 4 test cocks. Most water authorities require it to be tested and certified by a licensed backflow tester at installation and annually thereafter. It carries USC FCCCHR approval, which many jurisdictions accept as their sole approval list.
- What shutoff valves are included?
- It is supplied with outside screw and yoke (OS&Y) gate valves on the inlet and outlet. OS&Y gates give the visible open/shut indication that fire-line and many water-authority specs require.
- Is this listed for fire protection service?
- Yes — it is UL Classified and FM Approved, the listings normally required for a backflow device on a fire sprinkler supply.
Specifications
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Type: Double Check
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Size: 4"
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Inlet Size: 4"
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Outlet Size: 4"
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Body Material: Cast Iron
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Max Pressure (psi): 175
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Application: Domestic Water
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Backflow Protection: Both
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Operation: Continuous
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Country of Origin: United States
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Warranty: 1 Year Limited
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MPN: LF709-DOSY 4
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Certifications: ASSE-1015, CSA-B64, UL, FM, USC, IAPMO
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Lead-Free: Yes
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Assembly Type: Double Check
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Hazard Protection Level: Low Health Hazard
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ASSE Standard: ASSE 1015
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USC FCCCHR Approved: Yes
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Fire Protection Listing: UL Classified;FM Approved
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Field Testable: Yes
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Number of Test Cocks: 4
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Shutoff Valves: OSY Gate
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Flood Sensor (SentryPlus Alert): No
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Strainer Included: No
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Air Gap Fitting Included: No
